Abstract
Molecular flux distribution is critical information to obtain uniform thin films using the thermal evaporation technique in vacuum. However, the flux distribution is a quite complex function depending on the geometry of evaporation sources and the individual motion of evaporated molecules. This makes it difficult to establish a model describing the flux distribution that is directly associated with the distribution of film thickness on the substrate. In this study, we found that the conventional analytic model severely deviates from the experimental flux distribution except in the simple case. Thus, we developed a numerical model based on the Monte Carlo method to simulate the angular flux distribution from a thermal evaporation source. In particular, interparticle collisions have been handled rigorously. Evaporated molecules were assumed to be point particles that collide with each other and adsorbed (emitted) on (from) the nozzle wall of the source. The interparticle collision probability was addressed with the rarefied gas dynamics and the cosine law of emission was adopted to simulate the adsorption/emission process at the nozzle wall. Finally, we compared the simulated flux distribution with experiments on the cylindrical nozzle with various aspect ratios and deposition rates. The simulation results show excellent agreement with experimental data, indicating that interparticle collision is a key parameter for accurate simulation.
| Original language | English |
|---|---|
| Pages (from-to) | 1233-1237 |
| Number of pages | 5 |
| Journal | Current Applied Physics |
| Volume | 19 |
| Issue number | 11 |
| DOIs | |
| Publication status | Published - 2019 Nov |
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All Science Journal Classification (ASJC) codes
- Materials Science(all)
- Physics and Astronomy(all)
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Molecular flux distribution from the thermal evaporation source using Monte Carlo method : The importance of interparticle collision. / Hyun, Gyeongho; Kim, Sungmoon; Im, Jonginn; Na, Younghyuck; Jeong, Kwangho; Lee, Hyunbok; Yi, Yeonjin.
In: Current Applied Physics, Vol. 19, No. 11, 11.2019, p. 1233-1237.Research output: Contribution to journal › Article
TY - JOUR
T1 - Molecular flux distribution from the thermal evaporation source using Monte Carlo method
T2 - The importance of interparticle collision
AU - Hyun, Gyeongho
AU - Kim, Sungmoon
AU - Im, Jonginn
AU - Na, Younghyuck
AU - Jeong, Kwangho
AU - Lee, Hyunbok
AU - Yi, Yeonjin
PY - 2019/11
Y1 - 2019/11
N2 - Molecular flux distribution is critical information to obtain uniform thin films using the thermal evaporation technique in vacuum. However, the flux distribution is a quite complex function depending on the geometry of evaporation sources and the individual motion of evaporated molecules. This makes it difficult to establish a model describing the flux distribution that is directly associated with the distribution of film thickness on the substrate. In this study, we found that the conventional analytic model severely deviates from the experimental flux distribution except in the simple case. Thus, we developed a numerical model based on the Monte Carlo method to simulate the angular flux distribution from a thermal evaporation source. In particular, interparticle collisions have been handled rigorously. Evaporated molecules were assumed to be point particles that collide with each other and adsorbed (emitted) on (from) the nozzle wall of the source. The interparticle collision probability was addressed with the rarefied gas dynamics and the cosine law of emission was adopted to simulate the adsorption/emission process at the nozzle wall. Finally, we compared the simulated flux distribution with experiments on the cylindrical nozzle with various aspect ratios and deposition rates. The simulation results show excellent agreement with experimental data, indicating that interparticle collision is a key parameter for accurate simulation.
AB - Molecular flux distribution is critical information to obtain uniform thin films using the thermal evaporation technique in vacuum. However, the flux distribution is a quite complex function depending on the geometry of evaporation sources and the individual motion of evaporated molecules. This makes it difficult to establish a model describing the flux distribution that is directly associated with the distribution of film thickness on the substrate. In this study, we found that the conventional analytic model severely deviates from the experimental flux distribution except in the simple case. Thus, we developed a numerical model based on the Monte Carlo method to simulate the angular flux distribution from a thermal evaporation source. In particular, interparticle collisions have been handled rigorously. Evaporated molecules were assumed to be point particles that collide with each other and adsorbed (emitted) on (from) the nozzle wall of the source. The interparticle collision probability was addressed with the rarefied gas dynamics and the cosine law of emission was adopted to simulate the adsorption/emission process at the nozzle wall. Finally, we compared the simulated flux distribution with experiments on the cylindrical nozzle with various aspect ratios and deposition rates. The simulation results show excellent agreement with experimental data, indicating that interparticle collision is a key parameter for accurate simulation.
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U2 - 10.1016/j.cap.2019.08.010
DO - 10.1016/j.cap.2019.08.010
M3 - Article
AN - SCOPUS:85070511694
VL - 19
SP - 1233
EP - 1237
JO - Current Applied Physics
JF - Current Applied Physics
SN - 1567-1739
IS - 11
ER -